1. Field
The embodiments discussed herein relate to an electric power supply apparatus capable of reducing a standby power that is provided to an electric apparatus.
2. Description of the Related Art
In general, a standby power represents an electric power consumed when an electric apparatus does not perform its primary function or waits for power-on signals from external and internal parts while being connected to an external power source (nominal alternating current (AC) power source).
In many cases, some electric apparatuses—such as a television, an air conditioner, a microwave, a computer, and a charger of a mobile phone—consume a greater amount of electric power in a standby mode than during the time that they are in an operating mode during a day. An example is a home microwave.
Such an electric apparatus performs a power-saving standby mode when they do not offer any feature while being connected to a commercial AC power source. However, the electric apparatus is not completely disconnected from the nominal power source and thus consumes, for example, several hundreds of milliwatts or several watts.
In particular, some electric apparatuses activated by a remote will control—a television, an air-conditioner, and an audio system, for example—need to provide a minimum amount of electric power to a control unit including a remote control signal receiver even when the electric apparatuses are switched off. In this manner, when a user controls a switched-off electric apparatus by use of a remote control, the electric apparatus can receive a remote control signal transmitted from the remote control, and performs a function corresponding to the received remote control signal.
Accordingly, electric apparatuses controlled by a remote control further generate a predetermined amount of standby power to receive a remote control signal in a standby mode.
Such a standby power users approximately 11% of domestic power consumption in Korea, and in order to reduce the standby power, a lot of government regulations come into force and many technologies have been developed.
One method to reduce the standby power is by use of a technology in which the efficiency of power source generated is enhanced when the voltage is converted in a transformer. Another method to reduce the standby power is by use of a technology in which standby power is provided by use of a subsidiary standby power supply apparatus other than an electric transformer.
According to the technology of enhancing the efficiency of power generated when converting the voltage of a transformer, an AC power source supplied from a commercial power source is rectified, and then the rectified power is provided to a transformer so that the voltage of the transformer is changed to a power by intermittently controlling the switching device; and therefore the converted power is used as a standby power.
Most of the standby power in an electric apparatus is mainly consumed by a remote control signal receiving circuit, which may be configured to receive a signal from a remote control to control the power of the electric apparatus, or from a control circuit, which may be configured to receive a signal of an external power button, when the electric apparatus is in a standby state. Although the amount of power consumption is very small, the efficiency of a Switched-Mode Power Supply (SMPS) used to provide the standby power is significantly lowered and thus a power loss at an internal transformer occurs. In this regard, a number of technologies have been developed to enhance the efficiency of the SMPS in the standby mode, but it is difficult to reduce the standby power to the level of several milliwatts.
According to the technology of providing the standby power by use of a subsidiary standby power supply apparatus other than an electric transformer, a power is charged in a subsidiary standby power supply apparatus, such as a secondary battery or a super-capacitor, and the charged power is used as the standby power in the standby mode.
In this case, the power stored in the standby power supply apparatus is used as the standby power in a standby mode state, so a standby power in a normal state can be removed. However, the amount of power stored in the secondary battery is limited, so the secondary battery needs to be recharged after a predetermined time period of the secondary battery's use. In addition, since the secondary battery is recharged by use of a power source of the SMPS, more power is consumed than it requires to be recharged.
In addition, if the secondary battery is not recharged, the secondary battery is completely discharged and thus the electric apparatus does not operate properly.